Typically, when large area concrete floors are installed, they may be surface finished, e.g., texturized, cleaned, prepared for subsequent application of a penetrating sealer or other substance, using a surface processing machine, such as conventional walk behind floor polishing-type machines 20 comprising a gas or electric engine 22, a handle 24 for machine control and steering and a circular rotating brush 26 driven by engine 22, as shown in FIG. 1. Such machines have a typical finished area per revolution of less than 20 square feet. When it is appreciated that large warehouse floors may be hundreds of thousands of square feet, it can be seen that performing a finishing operation on large area floors using walk behind type brush machines will either take a very long time or require many operators and machines.
It is known that during the installation of concrete floors, the troweling and finishing operation is performed on the wet concrete using either walk-behind or ride-on power trowels. Inasmuch as at least one type of power trowel machine is generally already on site during the installation of concrete floors, the present invention seeks to use the on-site availability of these machines for surface finishing purposes. In addition, generally, concrete contractors do not have floor polishing machines on site and typically do not own such machines. Therefore, where conventional floor polishing machines are used to surface finish concrete surfaces, concrete contractors have to invest in and own or lease separate, expensive pieces of equipment.
In one of its forms, the present invention takes advantage of the larger finished area attainable with ride-on power trowel machines by converting these power trowel machines to surface finishing machines suitable for tasks other than troweling. Ride-on power trowel machines typically range in size from approximately 6 feet to slightly more than 10 feet in width and produce a troweled area of up to 40 square feet. The largest units weigh more than a ton and can finish about 30,000 square feet per day. Ride on trowels, such as the trowel machine illustrated in FIG. 2, can be configured with two or more rotors, each having a plurality of radially oriented, spaced-apart arms and a trowel blade mounted on each arm. The blades on adjacent rotors may be overlapping or non-overlapping. A typical four arm spider assembly suitable for use with either a ride-on or walk-behind power trowel is illustrated in FIG. 3. The assembly includes four radially extending arms emanating from a central hub, which receives a drive shaft. A trowel blade is mounted directly via bolts or indirectly via a mounting bar on each of the arms. Concrete surface processing machines having spider assemblies for non-rotatably mounting trowel blades, and the manner of attachment of the trowel blades to the spider arms are discussed in detail in U.S. Pat. No. 7,059,801—Snyder et al, the disclosure of which is incorporated herein by reference. Another means for rotatably mounting surface processing tools to spider arms is disclosed in U.S. Pat. No. 4,319,434—Brecha.
Converting walk-behind or ride-on troweling machines to surface finishing machines involves providing mounting means which allows the rapid, on-site substitution of finishing tools, such as circular brushes, on the spider arms in place of the trowel blades which were used during the installation of the concrete floor. The mounting means of the present invention has the advantage that it can mount surface processing tools, such as scrubbing, brushing, buffing, grinding and polishing tools, on the spider arms using readily available hand tools in a very short period of time without need for heavy or expensive equipment. The surface finishing tools are mounted to each of the spider arms, desirably using a mounting bar, in such a way that, as the spider arms rotate about the hub, each of the surface polishing tools, e.g., circular brushes, on each arm is free to spin about a mounting axis perpendicular to the spider arms and parallel to the axis of rotation of the spider arms. By allowing circular brushes to rotate freely about the axis, the brushes will wear more uniformly than if they were rigidly mounted to the arms.